1. Field of the Invention
The present invention is related to a heat sink, in particular, to an LED lighting device with an improved heat sink.
2. Description of Related Art
During the operation of LED, approximately 80% of the total energy is transmitted to the environment in the form of waste heat. However, the operation in high temperature can have significant effects on electronic components such as lifetime, product reliability and light decay.
A known LED light engine comprises a circuit board and a plurality of LED units electrically connected on the circuit board. With the heat sink provided on the LED light engine, the heat generated by the LED units can be dissipated via the heat sink such that the lifetime of the LED units can be extended, the reliability of the LED units can be increased and the light decay of the LED units can be reduced.
Furthermore, the aluminum extrusion or fin type of heat sinks only allows the air to enter at the direction parallel to the fins. When the heat sink is overly large, such as the surface area of the heat sink is too large or too long, the air cannot reach the center of the heat sink (i.e. the position of the heat generating unit) at all, which causes the effect of heat dissipation to be greatly reduced. To solve such problem, it is a common practice to introduce a cutting slot in the direction perpendicular to the aluminum extruded fins; however, the problem is still not being overcome completely due to the limited effects of insufficient width of the cutting slot. On the other hand, if the width of the cutting slot is too large, a large portion of the surface area of the fins for heat dissipation would be wasted, which is not only difficult in practice but also results in limited effects of heat dissipation.
In addition, the aforementioned heat sinks are only suitable for low-power LED lighting apparatus and heat sinks. For high-power LED light engines (such as 1000˜5000 W) of the present time, they are clearly insufficient; in view of above, there is a need for an improved heat sink applicable to high-power LED light engines and capable of achieving heat dissipation effectively.